Résumé : During the Chosun period (1392-1910), the Ming and Qing Dynasty of China implemented a policy of seclusion, so Koreans learned the Chinese language from other Koreans with old textbooks used as a Chinese translator. Only ambassadors who were delivering national documents could travel to foreign countries. Delegations going to China were called jocheon (朝天) during the Ming Dynasty, and yeonheng (燕行) in the Qing Dynasty. In the yeon-heng-lok (燕行錄) during the 17th century, there was no conscious effort to learn from the Qing Dynasty. The delegations sent to Japan, called tongshinsa (通信使), passed on mainland culture to Japanese intellectuals. The written conversations between the intellectuals of the two countries were immediately published to convey the mainland culture to Japan. But travelling journals written by delegations are one-sided records of a single, so the content cannot be assumed to be entirely true. Hence the need to examine cheok-dok (尺牘, letter), which are two-way communication between the sender and receiver, to supplement the flaws of sa-heng-lok.